The present invention is directed to a one-piece, molded plastic, or the like, closure that may be threaded onto the finish or neck of a container, and in which a tamper-indicating band is joined to the bottom of the closure skirt by a series of frangible bridges. An inwardly and upwardly turned flexible, stop band is molded inside the indicator band and in combination with a radial bead on the container finish will resist removal of the closure without rupture of the frangible bridges.
Tamper-indicating closures are not new and one recently patented example can be found in U.S. Pat. No. 4,394,918 issued to Jean Grussen on July 26, 1983. In this patent a threaded closure carries a hold ring that is joined to the bottom of the cap skirt by a series of breakable tabs and the hold ring has an inside diameter that is at least equal to the outside diameter of the cap skirt. A plurality of lock lugs supported on the ring are inclined upwardly and inwardly and are intended to hook behind a collar or mating ring on the container neck to prevent the hold ring from being lifted off the container neck when the cap is unscrewed. An unbreakable flange is provided between the cap skirt and the ring and serves as a hinge for the cap when it is unscrewed.
Other tamper-indicating closures that thread on the containers are made fairly simple, but these tamper-indicating rings generally require cooperating, specifically designed, means on the container.
Some other tamper-indicating systems have been used in which a frangible band is formed at the bottom of the closure skirt and requires the actual destruction of the band before the closure can be unscrewed. These also may require special ramps and ledges to be formed on the container shoulders or necks. The problem with these systems is that once the band is removed and discarded, it may not be readily apparent that the closure has been unscrewed.
Much of the same can be said for the systems that use heat shrunk or stretch bands that engage the closure and the container. Furthermore, heat shrinking adds an additional step to the sealing process and requires special equipment beyond the normal threaded closure applying machines.
In U.S. Pat. No. 4,350,844 and U.S. application Ser. No. 728,377, filed Apr. 29, 1985, U.S. Pat. No. 4,613,052, having a common assignee with the present application, there is disclosed and claimed a screw type cap of plastic with a tamper-indicating ring or band that is carried at the lower end of the skirt of the closure with frangible bridges forming the connection. The removal of the closure results in the indicating band being severed from the closure and the band is moved to a lower position on the neck and is prevented from being returned to its, as applied, position. A container has a finish, below external threads which is formed with an inwardly and downwardly tapering side wall which leads to an abrupt, horizontal ledge such that when an indicating band is severed from a closure, on removal, the band falls below the ledge and cannot be returned. The closure is formed with internal threads in the skirt and at the bottom of the skirt a band or ring of about the same external diameter as the cap is formed with frangible bridges joining the band to the skirt. Within the indicating band an inwardly extending flexible stop ring is formed integral with the indicating band. A particular finish on the container provides a pair of radial ledges which extend outwardly below the threads on the container neck. These ledges are vertically displaced relative to each other and are joined by an inwardly tapering wall which is adapted to form the surface on which the stop ring will be seated when the closure is applied. The stop ring prevents removal of the closure without the separation of the indicating band from the closure skirt.
Among the objectives of the present invention are to provide a tamper indicating package wherein the tamper indicating band is positively caused to dropped away from the closure after being severed and an intermediate tapered or concave portion between the two beads so that a user can readily see and feel that the band has been severed.
In accordance with the invention, the tamper indicating package comprises a one-piece molded closure of plastic which threads onto a container such that when the closure is unthreaded, a tamper-indicating ring becomes separated from the lower end of the closure skirt. The indicating ring or band is joined to the closure along a weakened frangible line and a flexible stop ring is formed within the band and extends inwardly and upwardly when the closure is applied to a container finish. The container finish has a first radial bead, a second radial bead spaced axially below the first bead, and an intermediate tapered or concave surface between the first radial bead and second radial bead. A further surface extends from the second bead axially downwardly and radially inwardly and the flexible end of the stop ring rests on this surface between the two beads, when the closure is applied. When the closure is unthreaded to remove it, the free end of the stop ring passes over the second bead into the recess formed by the surface between the two beads and the frangible portion is broken leaving the ring and band in this position. Upon subsequent reapplication of the closure, the closure skirt engages the band causing the band to pass over the second bead on the finish so that the band falls away but remains on the container to indicate that the band has been severed.